Means for forming tubular articles by extrusion.



uly 15, 1919. Z SHEETS-SHEET 1- Patented J APPLICATION HLED APR-25.1917.

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l. W. LEIGHTON AND O. J. P. CRICK. MEANS FOR FORMING TUBULAR ARTICLES BYEXTRUSION -1. W. LEIGHTON AND O. J. P. CHICK. MEANS FOR FORMING TUBULARARTICLES BY EXTRUSION.

APPLICATION FILED APR-25.1911.

Patented July 15, 1919.

2 SHEETS-SHEET 2.

in V6 10m.

JOHN W. LEIG-HTON AND OWEN J". P. CEICK, OF TORONTO, ONTARIEO, CANADA,AS-

SIGNORS TO PRESSED METALS, LIMITED, OF TQRUNTO, ONTARIO, CANADA, A.

oonroas'rion'.

MEANS FOR FORMING TUBULAR ARTICLES BY EXTRUSIQN.

Specification of Letters Patent.

Patented July 15, 1%19.

Application filed April 25, 1917. Serial No. 16%,535.

To all whom it may concern:

Be it known that we, JOHN Wromrrn LEIGHTON and OWEN JOHN Prr'rs CRIGK,both subjects of the King of Great Britain, and residents of the city ofToronto, county of York, Providence of Ontario, in the Dominion ofCanada, have invented certain new and useful Improvements in Means forForming Tubular Articles by Extrusion, as described in the followingspecification. and illustrated in the accompanying drawings, that formpart of the same.

Many attempts have been made to form tubular metal articles by a processof extrusion from metals which require to be heated to obtain thenecessary fluidity but none have been successful for various reasons andit is the principal object of this invention to overcome thedifiiculties due to the choking of the tools by the fluid metal and theseizing of the formed articles due to contraction in cooling.

A further object of the present invention is to produce tubular articlesof comparatively short length very rapidly by the use of quick operatingmachines, such as a punch press, requiring the minimum of labor andmaterial, thereby cheapening the cost of production and effecting highquantity production.

A further and important object is to enable the production by extrusionof tubular articles having variations in their diametral dimensionsthereby effecting a great saving in material which is extremelyimportant in the making of war munitions for which this invention isprimarily adapted.

The principal feature of the invention consists in the novel manner ofhandling a heated metal billet whereby the metal is forced through thethroat of the die around a central mandrel which operates coincidentwith the plunger and the external and internal dimensions of theproduced articles are definitely formed in confinement between the wallsof said die and mandrel.

A further important feature of the invenis a vertical sectional View ofa plunger and die and the ram of a press used in carrying this inventioninto effect, the plunger being shown in the raised position.

Fig. 2 is a sectional view similar to Fig. 1 showing the relation of theparts when the plunger is in an intermediate position.

Fig. 3 is a sectional view similar to Figs. 1 and 2 showing the alteredrelation of the parts in the advanced position at about the completionof the power stroke'of the ram.

Fig. i is an enlarged sectional. View of the plunger and die showing anintermediate and fully advanced position in dotted lines. Fig. 5 is aperspective view of the finished tube.

In carrying the present invention .into effect We utilize a quickoperating machine such as a punch press upon the bed of which the die 2is placed. The die is formed of an upper member 3 having a pocket ltherein in which the heated billet from which the article is to be madeis placed.

A die block 5 is arranged within the upper member 3 at the bottom of thepocket 4, the

die being of a lesser diameter than saidpocket and having the beveledthroat 6 leading from the pocket 4 to the recess 7 which forms thelarger upper portion of the tubular article to be made.

A secondary throat 8 is formed in the die block 5 reducing the diameterof the die opening to the size and shape of the eX- ternal diameter ofthe smaller portion of the tube to be produced. The remaining length ofthe die is formed by a plurality of die blocks 9 secured in the main die2. The plunger 10 secured to the ram 11 of the press is adapted to enterthe pocket 4- to press the material of the billet into the die and saidplunger is provided with a central orifice 12 in which is located thepilot mandrel 13. The former 13 is slida-bly arranged in the plunger andthe upper end thereof is formed with a head 14- secured in a cylindricalblock 15 slidably arranged within a cylindrical recess 16 axiallyarranged within the ram of the press and adapted to be reciprocatedtherein. The upper end of the block 15 is formed with an opening 17 intowhich the end of the lever 18 projecting through a slot 19 in the sideof the ram extends.

The outer end of the lever 18 is carried upon a fixed pivot 20. Afulcrum 21 is secured to the ram beneath the lever 18 and is adapted inthe movement of the ram to engage the underside of the lever 18. Thelever is held in engagement with the block 15 carrying the mandrel 13and also in contact with the fulcrum 21 by a coil compression spring 22-encircling the rod 23 pivotally connected to. said lever and slidablyextending through a guide 24 arranged on the press.

In the operation of this process the billet 25 which is perforatedcentrally is first heated to the desired teinperature and is then placedin the pocket 4 and the ram of the press is brought downwardly. As theram moves downwardly the lever 18 swinging upon its fixed pivot andbeing fulcrumed on the fulcrum 21 moves the mandrel 13 downwardly at aspeed greaterthan that of the punch so as to project from the end of thepunch a sufiicient distance to extend through and beyond the bottom ofthe billet and approximately to the throat 8' just prior to theengagement of the billet by the plunger 10.

The pressure of the plunger 10 flows the material of the billet throughthe contracted throat 6 into the recess 7 and as the plunger thus movesinwardly into the die the mandrel 13 is advanced by the action of thelever 18 at a speed faster than that of the plunger to and past thesecondary throat 8. The block 15 carrying the mandrel 13 then bottoms inthe recess 16 and continues to move inwardly with the plunger andprojects well intothe restricted portions of the die. The metal flowsthrough the constricted throat 8 to form the reduced portion of the tubeand as the mandrel 13 extends well into this restricted portion themetal is thoroughly set to the altered shape before being released fromthe restriction between the mandrel and the walls of the die. The resultof this condition is that the dimensions of the finished tube areaccurately determined and a uniform product results.

Immediately upon the cessation of the inward movement of the plunger thepressure is released and the tube immediately con tracts and seizes uponthe mandrel 13 and as the plunger is withdrawn in its return movementthe tube is partly withdrawn from the die, thereby obviating anytendency.there may be of the tube sticking in the die and avoidingdifficulty in releasing.

As the plunger continues its upward movement the fulcrum 21 engages theunderside of, the lever 18 and causes the end of the lever engaging theblock 15 to move upwardly at a faster speed than the punch consequentlylifting the cylindrical block 15' 7 from the die and the plunger.

thereto. The mandrel is thus automatically and forcibly withdrawn fromthe tubular member formed and consequently releases the tube practicallyinstantaneously, both The operation of forming tubular members in themanner described is extremely rapid, the billets are inserted into thedie and the press is tripped and the plunger is brought down with aquick sharp movement. The mandrel is operated to move independently andin advance of the plunger and the material of the billet is extrudedinto the forming die very rapidly. The downward movement of the mandrelcoincident with the flow of the metal effectively prevents the metalbeing forced upwardly between the mandrel and the plunger, which wouldcause the mandrel to seize in the plunger and prevent its operation inwithdrawing from the finished tube and it also has a beneficial effe'ctupon the grain or texture of the metal and obviates malformation.

The method of operation of the former is herein described as having amovement independent of the plunger in the downward movement thereof,but it mustbe understood that this movement is not essential so long asthe mandrel is arranged to project through the billet and into the dieand past the throats thereof in advance of the flowing metal, but theindependent movement of the mandrel'in the return or withdrawingmovement of the plunger is most essential to the success of theoperation in order to free the mandrel from the contracted tube.

The confining of the material forming the article between the wall ofthe die and the mandrel. after passing the throat is extremely importantas it maintains the positive dimensions of the article formed in such amanner as to produce positive and definite results.

A further and important feature is the forming of an article of severaldiameters in a single operation as a comparatively short and heavybillet which will properly hold the required heat may be used and themetal is extruded to form a tube of any desired gage or thickness whichmay have a heavier portion at one end which will have sufiicient stockfor threading or for any other' purpose desired.

- What we claim as our invention is 1. Means for forming tubulararticles by extrusion, comprising a die, a plunger adapted to enter thedie, and a mandrel arranged in the plunger and adapted to enter the diein advance of the plunger and to be withdrawn from the formed tube in amovement independent of the plunger.

2. Means for forming tubular articles by extrusion, comprising a die, aplunger adapted to enter the die, and a mandrel arranged in the plungerand adapted to be operated to 1% extend into the die in advance of theplunger and to move with. said plunger in the extruding operation and tobe withdrawn with said plunger with an accelerating movement faster thanthe plunger.

{3. Means for forming tubular articles by extrusion, comprisinga dieadapted to confine the billet and having a reduced throat through whichthe metal of the billet is to be extruded, a plunger adapted to entersaid die and force the metal through the throat,

. a mandrel slidably arranged in said plunger and adapted to extendthrough the throat of the die, and means for moving said mandrelcoincident withand in advance of said lunger in the extruding operationand wit drawing said mandrel coincident with the plunger with anaccelerating move ment to strip the finished tube therefrom.

4. Means, for forming tubular articles by extrusion comprising a dieadapted to conto operate said mandrel to withdraw it into the plungerduring the return movement of said plunger.

5. Means for forming tubular articles by extrusion, comprising a diehaving a recess at the top to confine the billet, a reduced portionbelow said recess and a further reduced portion, a plunger adapted toforce the metal into the reduced portions of the die,

and a mandrel adapted to extend through the billet and into the finallyreduced portion of the die to form with said die a passage of positivedimensions to receive the extruded metal.

6. Means for forming tubular. articles by extrusion, comprising a dieadapted to con fine the billet and having a reduced throat through whichthe metal'of the billet is to be extruded, a plunger adapted to entersaid die and force the metal through the throat, a mandrel slidablyarranged in said plunger and adapted to extend through the throat of thedie, a lever carried on a fixed pivot and having its free endoperatively connected with said mandrel, and a fulcrum member operatingwith the plunger adapted to engage said lever intermediate of its lengthto effect the accelerating movement of the mandrel in its downward andupward movements.

' 7. Means for forming tubular articles by extrusion, comprising a dieadapted to confine the billet and having a reduced throat through whichthe metal of the billet is to be extruded, a plunger adapted to entersaid die and force the metal through the throat, a mandrel slidablyarranged in said plunger and adapted to extend through the throat of thedie, a lever carried on a fixed pivot and having its free endoperatively con nected with said mandrel, a fulcrum member operatingwith the plunger adapted to engage said lever intermediate of itslength, and a compression spring operating against said lever to hold itin contact with said fulcrum member for the major portion of thedownward movement of the plunger.

J. W. LEIGHTON. OW'EN J. P. ORICK.

